During the forthcoming year, the rebreathing technique for measuring pulmonary tissue volume will be modified in attempt to permit more reproducible values. Once thi modification is complete, correlations will be made with wet weight to dry weight ratios of the lung in sheep with induced pulmonary edema. After validating the method, studies on patients with cardiovascular disease and pulmonary congestion will be undertaken. In addition, the rebreathing technique will be used during antigen challenge in patients with allergic asthma. Finally, monitoring of respiration, mechanics of breathing and arterial oxygen saturation will be obtained in sleeping normals and patients with chronic obstructive lung disease.